Marine well drilling apparatus



Jan. 15, 1957 c. G. WILLIS ET AL 2,777,669

MARINE WELL DRILLING APPARATUS 5 Sheets-Sheet 2 Filed Dec. 27, 19486021/6008 6. M/aus UAW/0 6: 14 1408 7 INVENTORS 6.;

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' rrae/ves s Jan. 15, 1957 7 C. G. WILLIS ET AL MARINE WELL DRILLINGAPPARATUS Filed Dec 27, 1948 5 Sheets-Sheet 5 DflV/D 6. [rt musINVENTORS c. e. WILLIS ET AL 2,777,669

MARINE WELL. DRILLING APPARATUS 5 Sheets-Sheet 4 G PV/LL/s 3 H4405JNVENTORS A7770EA/5V5' 8 lllllllfi CoeA/Euus' Oar/0 Jan. 15, 1957 FiledDec Jan. 15, 1957 c. G. WILLIS ET AL 2,777,669

MARINE WELL DRILLING APPARATUS Filed Dec. 27, 1948 5 Sheets-Sheet 5Coma/us 6*. H0415 OflV/D G PV/Lus INVENTORS Unite States Patent eeMARINE WELL DRILLING APPARATUS Cornelius G. Willis and David G. Willis,Los Ang ele s, David G. Willis assignor to said Cornelius ApplicationDecember 27, 1948, Serial No. 67,518

8 Claims. (Cl. 255-25 This invention relates to a submerged buoyantsupport and is particularly directed to s uppor ting devices for use inthe ocean orother large bodies of water, which devices may be used foroil well drilling or production operations or for other purposesrequiring rigid artificial supports such as, for example, floating docksor air dromes. While various types of submerged buoyant supports are.described hereinafter in connection with oil well drilling operations,it will be understood that the advantageous features of our inventionare not confined to this particular use. I I I A primary object of ourinvention is to provide a support for marine oil .Well equipment whichmay be employed in relatively deep water.

An important object of this invention is to provide an artificialsubmerged or partly submerged island, platform or false bottom which hassuificient buoyancy to support conventional rotary drilling equipment,casing, etc, and which may be maintained below its normal floatingposition by means of the plurality of cables, chains or other elementsattached tothe ocean bottom. Our submerged buoyant support difr'ersfroma barge or boat floating on the surface because such a vessel must riseand fall with the tide and is afiected by wave action. Our submergedbuoyant support differs from barges which may be sunk to rest on thebottom in relatively shallow water, because such barges are not useablein deep water for well drilling operations.

Another object of our invention is to provide a submerged buoyantsupport for well drilling apparatus, the support being positioned belowthe surface for a suflicient distance to avoid adverse effect of Waveaction and tides.

Another object is to provide a novel form of marine well drillingsupport utilizing laterally extending compression members to which guywires from the derrick structure and ocean bottom may be attached forobtaining lateral stability.

Another object is to provide novel means for varying the buoyancy of thesubmerged support.

A related. object is to provide supporting structure including aplurality of relatively long vertical buoyant pilings, each having ahigh center of buoyancy and a low point of attachment for a guy wireextending to the ocean bottom, whereby each of the pilings has inherentlateral stability. I

A further object is to provide a submerged buoyant support havingrelatively great horizontal dimensions as compared to its verticaldimensions, depending for late ral stability upon its width and rigidityand being tied to the ocean bottom by a plurality of tension members.

Other more detailed objects and advantages will appear hereinafter. I

in the drawings: I

Figure 1 is a side elevation in diagrammatic form illustrating apreferred embodiment of our invention. I I I Figure 2 i s a sideelevation partly broken away shown on an enlarged scale and illustratingthe details of construction of the buoyant member.

1'=i 'u'r 13.is a sectional v ele v aticni showing constru c tiona ldetails of anc horing the upper and lower ends of the tubular ten sion'elment. I I I I I Figure 4 is a plan view partly broken away taken substantially on the lines 44 as shown in Figure 2. I

Figure 5 is a side elevation in diagrammatic form showing amodification. I I II I I Figure 6 is a side elevationpartly in sectionshowing details of constructionand anchorage of the buoyant membersshown in figure 5 I I I II Figure 7 is a sectional detail showing theconstruction of the upper end of the buoyancy control extensionsernployed in connection with each of the buoyant members shown in FigureI I I I I I II I Figure 8 is a sectionalplan view taken substantially onthe lines 88 as shown in Figure 5. II I I Figure 9 is a sectionalelevation taken substantially on the lines 9--9 as shown-in Figure 6. I

I Figure 10 is a side elevation in diagrammatic form showing a furthermodification. I I

Figure 11 is a plan view of the buoyant member illustrated in Figure 10.I II I Refern'ngto the drawings, the rotary well drilling apparatusincludes a derricklt) and drilling platform 11 adapted to be supportedover a body of water 12. The derrick 1.0 is carried on a substructure 13which extends downwardly below the water leve l 14 and rests on theupper end of the floating or buoyant member 15; This buoyant memberdisplaces a relatively large amount of water in comparison to its weightand would normally float almost completely out of the water. The buoyantmember 15 is maintained in a submerged position below its normal freefloating position by means of a tension element 16 which may comprise aconductor casing made up or" a plurality of joints connected end to end.The conductor casing 16 extends downwardly from a location adjacent thedrilling platform 11 through the buoyant member 15 and is secured to theocean floor by the cement body 17. The buoyant member 15 may includeacylindrical portion 18 having a conical cap 19 at its upper end and afrusto-conical lower projection 19a extending downwardly therefrom. Acenter pipe 20 extends axially through the buoyant member 15 and isfixed at the upper and lower ends thereof by any convenient means suchas by welding. As shown in Figurejlv the center pipe 20 is secured to,the conductor casing 16 by means of a pipe slip assembly generallydesignated 21. This slip assembly includes a plurality of wickered slipelements 22 constrained to move on a tapered mandrel 23 and to move intoengagement with the inner wall of the conductor casing 20. The slipassembly 21 therefore tensions the conductorcasing 16 and enables it tohold the buoyant member 15 below its normal free floating position.

A plurality of struts 24 extend radially outwardly from the buoyantmember 15. These struts 24 preferably are submerged below the waterlevel 14- and may be attached to the buoyant member 15 by means offittings 25. The outer end of each strut is provided with a terminalfitting 26. A guy wire 27 extends from each terminal fitting 26 to theupper portion of the derrick 19. Hold-down cables 23 also extend fromthe fittings 26 to the anchor blocks 29 resting on the ocean floor 30. IInclined hold-down cables 3 1 also extend from the anchor blocks to thebuoyant member 15 for stability against lateral movement.

It is contemplated that the drilling equipment to be employed ontheplatform 11 and in the derrick 16 shall be of conventional form. I In'such case the total weight carried bjth e substructure 13 vari es overa wide range. 1 3 7. the i e' at a issu n ea a s h a load may besupported by the derrick 11), whereas during initial stages in thedrilling operation the load on the derrick 10 asteatea Jen. is, ids? 3may be very low. If the buoyancy of the member 15 were constant thetension in the casing 15 and in the holddown cables 31 would vary over awide range. The tension would be at a maximum when the load on thederrick was at a minimum, and vice versa. In order to avoid this widevariation in tension and in order to reduce the required size of thecables and casing 16 means are provided for varying the buoyancy of themember 15 to compensate for the variation in weight carried by thederrick 10. As shown in the drawings this means includes a spear tube 32which extends downwardly through the pipe 33 which is fixed in the cap19 of the buoyant member 15. A stuffing box 34 of the type'shown inFigure 7 is mounted at the upper end of the pipe 33 to permit the tube32 to be drawn axially therethrough. A side outlet 35 is provided whichmay be connected to any convenient source of air pressure. When it isdesired to decrease the buoyancy of the member 15, water is pumped intothe upper end of the tube 32 so that it is delivered into the interiorof the member 15. When it is desired to increase the buoyancy, airpressure isadmitted from the side outlet 35. The pressure within themember 15 then forces water upwardly through the spear tube 33. Bymoving the tube 32 to position the lower end thereof at the desiredlevel, the amount of water remaining in the interior of the buoyantmember 15 may be accurately controlled. I prefer to taper the lower end19 er the'buoyant member 15 so that the collapse strength of the memberincreases as the depth of water increases. This simplifies theconstruction of the vessel and permits the use of uniform thickness ofmaterial for the wall thereof.

Internal bracing struts 36 may be provided for stiffness, and additionalinternal framework or struts may be utilized if desired. In operationthe buoyant member 15 with its integral center pipe 20 is floated toposition while partly filled with water to reduce its buoyancy. Theanchor blocks 29 are placed in position on the ocean floor and the guywires 31 are installed to hold the member 15 against lateral movement.The horizontal struts 24 are placed in position and the guy wires 27 andhold-down cables 28 installed. The rotary drilling equipment on thederrick platform 11 or on an attendant barge (not shown) is thenutilized in a conventional manner to lower the conductor casing 16through the center pipe 20. A drill bit 37 is carried on the lower endof the casing 16 and when it reaches the ocean floor 30 the casing 16 isturned by means of the rotary drilling equipment to cause the drill bitto cut into the ocean floor. If necessary, mud fluid is delivered underpressure to the interior of the casing 16 to carry the cuttings awayfrom the bit. After the bit has entered the formation for apredetermined distance, cement is pumped down through the interior ofthe casing 16 to fill the drilled hole with the cement body 17. ghisserves to anchor the casing 16 relative to the ocean oor.

The member 15 is reduced in buoyancy by adding water to the interiorthereof through the spear tube 32 so that the center pipe 20 is loweredslightly with respect to the conductor casing 16. The slip assembly 21is then actuated to secure the lower end of the center pipe 20 to thecasing 16. The buoyancy of the member 15 is then returned to its propervalue by forcing water from the interior thereof out through the speartube 32. A drill pipe 38 is then run into the conductor casing 16, andthis drill pipe is provided with a metal cutter 39 at its lower endwhich cuts a hole through the bit 37. The drill pipe 33 and metal cutter39 are then-withdrawn in order that a conventional formation drillingbit (not shown) may be installed on the lower end of the drill pipe. Thedrilling operation then proceeds in the conventional manner.

The buoyant member 15 is preferably maintained at a level below wave andtide action so that a stable foundation mounting is provided for thesubstructure 13 and derrick 10. The substructure 13 is preferably formedso that it offers a minimum of resistance to wave action.

The drilling platform 11' is located well above the high water level andout of reach of waves at high tide. The

' buoyancy of the member 15 may be varied to compensate for changes inweight supported on the derrick 10.

The modification shown in Figures 5 to 9 supports the derrick 10 anddrilling platform 11 above the action of waves at high tide as set forthabove. Instead of employing a single buoyant member, however, a largenumber of hollow pilings 50 are employed and are distributed under theplatform 11 and clustered in groups 51 under the legs of the derrick 10.Suitable substructure 52 including attached to concrete blocks 54resting on the ocean floor 55. As shown in Figure 8 the groups orclusters 51 may each include a plurality of individual buoyant pilings50 each comprising a length of pipe sealed at its ends. The groups maybe lashed together by suitable cable 56.

Means are provided for anchoring the lower end of each of the buoyantpiling 50 with respect to the ocean floor 55, and as shown in Figure 6this means may include a hold-down cable 57 secured to the lower end ofthe piling at 58 passing around a pulley 59 anchored to the concreteblock 60. The cable then passes upwardly through the slip housing 61also carried at the lower end of the buoyant piling 50. A tapered slip62 within the housing acts to prevent upward movement of the buoyantpiling 50 with respect to the stationary cable 57. The cable may extendupwardly through a guide 63 near the upper end of the buoyant piling 51and pass over a pulley 64 on the derrick platform 11. Suitable means(not shown) are provided for securing the upper end of the cable 57 withrespect to the platform 11. Suitable means are provided for varying thebuoyancy of each of the buoyant pilings 50, and as shown in the drawingsthis means includes an extension pipe 65 welded to the upper closure 66of the piling 50 and extending upwardly to the derrick platform 11. Astuffing box assembly 67 is located on the upper end of the pipe 65 topermit the spear tube 68 to be moved vertically therein while preservinga seal at the point where the spear tube enters the pipe 65. Compressedair admitted through the lateral inlet 69 is effective to force waterfrom the interior of the piling 50 out through the spear tube 68 in thesame manner as ,described in connection with the embodiment of ourinvention shown in Figure 2. Water may be added to the interior of thepiling through the spear tube 68 if desired.

Crossbracing 70 may be provided to connect the upper end of the clusters51 and to provide lateral support for the center pipe 72 which extendsupwardly adjacent the level of the drilling platform 11; The conductorcasing 73 may be installed and anchored by means of the cement securedto concrete blocks resting on the ocean floor 106. In this form of ourinvention lateral stability is afforded by the width and rigidity of thebuoyant member itself. The hold-down cables 104 and the conductor pipe107 maintain the member 100 in horizontal position and hold it submergedbelow wave and tide. action. The arms 102 may be attached to the centralbody 101 by any convenient means such as, for example, by bolting or bywelding. A slot 108 may be provided on the body for reception of thecenter pipe 110 which extends downwardly from the drilling platform 109.Companion plates 111 connected by bolts 112 extend across the slot 108to compensate for the loss of stiffness occasioned by the slot 108. Theplates 111 may be removed if desired after completion of the well inorder that the buoyant member 100 may be removed laterally from thecenter pipe 110.

Means are provided for varying the buoyancy of the arms 102 and body101, and as shown in the drawings this means may include the stationaryupright pipes 114 having movable spear tubes 115 mounted concentricallywithin them. The manner of introducing and discharging water fi'om eachof the buoyant units making up the member 101 may be substantiallysimilar to that described above. The derrick 116 rests on thesubstructure 117 which in turn is supported on the body 101. The legs ofthe substructure 117 are preferably positioned as shown at 118.

The conductor pipe 107 extends downwardly through the center pipe 110and is anchored in the concrete block 119 which rests on the ocean floor106. This block may be conveniently formed by placing a shell 120 on theocean floor and then pumping it full of concrete delivered through theconductor pipe 107. The conductor pipe 107 may be anchored with respectto the center pipe 110 by means of a slip assembly (not shown) whichmaybe similar to that illustrated in Figure 3. After the concreteforming the block 119 has se a drill string is run in through theconductor pipe 107 to drill out the cement plug and drill into theformation below the ocean floor 106 in the conventional manner.

While we have described the device in connection with the rotarydrilling apparatus, it will be understood that any form of well drillingapparatus may be employed.

Having fully described our invention, it is to be understood that we donot wish to be limited to the details herein set forth, but ourinvention is of the full scope of the appended claims.

We claim:

1. A buoyant load-carrying support floating in a body of water in asubmerged position, the support including a plurality of horizontallyextending buoyant arms radiating from a central body, structuralelements carried on the body and extending upwardly above the waterlevel to carry a load, and hold down cables at the ends of the armsengaging means on the floor of the body of water for maintaining thesupport in submerged position.

2. A support for a marine oil well installation including a derrick,comprising in combination a plurality of submerged horizontallyextending buoyant arms radiating from and secured to a central body,structural elements carried on the body and extending upwardly above thewater level to carry the oil well derrick, and hold down means at theouter ends of the arms engaging means on the ocean floor for maintainingthe support below wave and tide action.

3. A support for a marine oil well installation including a derrick,comprising in combination a plurality of submerged horizontallyextending buoyant arms radiating from and secured to a central body, thearms tapering from a relatively large cross-section adjacent the body toa relatively small cross-section at their outer ends, structuralelements carried on the body and extending upwardly above the waterlevel to carry the oil well derrick, and hold down means at the outerends of the arms engaging means on the ocean floor for maintaining thesupport below wave and tide action.

4. A support for a marine oil well installation including a derrick,comprising in combination a buoyant member having a plurality ofsubmerged horizontally extending arms, means for maintaining the supportbelow wave and tide action, said means including hold-down cables at theouter ends of the arms engaging means on the ocean floor,

said means also including a tubular tension element secured relative tothe body and having its lower end fixed in a block resting on the oceanfloor.

5. Supporting apparatus for a marine oil well installation including aderrick, comprising in combination: a floating member adapted to supportthe derrick, a plurality of tension elements secured to the ocean floorand adapted to maintain the floating member at a level below itsfree-floating position, a plurality of submerged compression strutsradiating outwardly from the floating memer, guy wire means attached tothe denick and extending to the outer ends of said struts, and cablemeans extending from the outer ends of the struts and secured to theocean floor.

6. Supporting apparatus for a marine oil well installation including aderrick, comprising in combination: a submerged floating member adaptedto support the derrick, a plurality of tension elements secured to theocean floor and adapted to maintain the floating member in a submergedposition below wave and tide action, a plurality of submergedcompression struts radiating outwardly from the floating member, pivotmeans connecting the inner ends of the compression struts to thefloating member, guy wire means attached to the derrick and extending tothe outer ends of said struts, and cable means extending from the outerends of the struts and secured to the ocean floor.

7. A buoyant load carrying support floating in a body of water in asubmerged position, a support including a plurality of horizontallyextending arms radiating from a central body, structural elementscarried on the body and extending upwardly above the water level tocarry a load, and hold down cables at the ends of the arms securedrelative to the floor of the body of water for maintaining the supportin submerged position.

8. In combination: marine oil well apparatus including a platform and aderrick mounted upon the platform, a fully submerged floating memberconstituting the sole supporting means for said apparatus and positioneddirectly below the derrick, the member having a centrally positionedvertical opening extending therethrough, structural framework meansextending upwardly from the submerged floating member to maintain thesaid apparatus above water level, means providing a vertical conductorconduit for well tools extending from above water level and axiallyinsertable centrally through said vertical opening in the submergedfloating member to the ocean floor, and inclined tension elementssecured to means on the ocean floor and to said floating member formaintaining said floating member in submerged position and for minimizing lateral movement thereof.

References Cited in the file of this patent UNITED STATES PATENTS 62,870Moody Mar. 12, 1867 138,293 Stoner Apr. 29, 1873 398,035 DieuleveultFeb. 19, 1889 424,544 Donnelly Apr. 1, 1890 1,159,519 Menier Nov. 9,1915 1,811,761 Roberts June 23, 1931 1,840,324 Lindquist Jan. 12, 19322,187,871 Voorhees Jan. 23, 1940 2,351,449 Noble June 13, 1944 2,399,611Armstrong May 7, 1946 2,399,656 Armstrong May 7, 1946 2,476,309 LangJuly 19, 1949 2,503,516 Shrewsbury Apr. 11, 1950 2,512,783 Tucker June27, 1950 FOREIGN PATENTS 466,985 Great Britain June 9, 1937

